/*
 * Copyright (c) 2010-2011, okazoh_tk. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *  - Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *  - Neither the name of the copyright holder nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef ALKES_TREE_RESOURCE_H_INCLUDED_
#define ALKES_TREE_RESOURCE_H_INCLUDED_

#include "alkes/tree/internal.h"
#include "alkes/core/ClassID.h"

namespace alkes {

class ListenerChain;
class Scene;
class Element;
class resource_ptr_base;

/// \addtogroup scenegraph
//@{

class AL_TREE_EXPORT Resource
{
    AL_DECLARE_ROOT_CLASS(Resource);

public:
    Resource();
    virtual ~Resource() = 0;

    void update(Scene* owner);

protected:
    void notify();
    virtual void onUpdate(Scene* owner);

private:
    friend class resource_ptr_base;

    void addListener(resource_ptr_base* listener);
    void removeListener(resource_ptr_base* listener);

    void destroyListeners();

private:
    ListenerChain*  listeners_;
};

///@cond

class AL_TREE_EXPORT resource_ptr_base
{
public:
    explicit resource_ptr_base(Resource* ptr);
    ~resource_ptr_base();

    void registerResource(Element* owner, Resource* resource);

    Resource* get() const { return resource_; }
    Element* getOwner() const { return owner_; }

private:
    void* operator new(size_t);
    void operator delete(void*);

    friend class Resource;
    void reset();

private:
    Resource* resource_;
    Element* owner_;
};

///@endcond


template<class T>
class resource_ptr
    : public resource_ptr_base
{
public:
    explicit resource_ptr(T* ptr)
        : resource_ptr_base(ptr)
    {
    }

    ~resource_ptr()
    {
    }

    operator T* () { return static_cast<T*>(get()); }
    operator T* () const { return static_cast<T*>(get()); }

    T* operator->() { return static_cast<T*>(get()); }
    const T* operator->() const { return static_cast<T*>(get()); }

    T& operator*() { return *static_cast<T*>(get()); }
    const T& operator*() const { return *static_cast<T*>(get()); }
};

template<class T, class U>
T resource_cast(const resource_ptr<U>& rsc)
{
    return !rsc ? 0 : (T)(*rsc);
}

#define AL_DECLARE_RSC(name, parent)    AL_DECLARE_CLASS(name, parent)

//@}

}

#endif
